Radio problems

kazanskykazansky Member Posts: 9
edited March 2014 in Subaru

the radio on my '99 Legacy resets after turning off ignition key for even a few minutes like I would disconnect a battery cable. Why is that happening and what's the solution? Is it time to purchase a new stereo system?

Please help.


  • swschradswschrad Member Posts: 2,171
    there is generally a second hot wire, that runs basically no current, in your typical modern stereo that is a keepalive for the memory circuit.

    there ought to be a MaxiCap or GoldCap electrolytic on there to provide a few days of power storage, but I digress.

    whatever other little-used circuits share that fuse, check 'em out, I bet you need a new fuse.

    if that's not it, you probably have a dead path inside the radio, it's dealer swap or replacement time. but check fuses and connections first.
  • dpannazzodpannazzo Member Posts: 2
    Have a similar problem with my 2000 Chevy Impala.
    When left for a few days the radio loses it's presets. Sometimes the preset memories restores itself. The clock however keeps time.
  • kazanskykazansky Member Posts: 9
    will check it out as per your suggestion this weekend

  • swschradswschrad Member Posts: 2,171
    ahhh, the infamous intermittent. or is it?

    remember, the golliwog new radios just about all have a "keepalive" wire going to battery that really only carries a few milliamps from another fuse. the idea here is that using two sources with diode ORing inside the radio means that as long as the battery is supplying power, there should be power going to the memory of the radio from one of the two sources.

    there is always the possibility of a bad contact in the wiring harness, especially since this is a steady trickle going into the radio. a few shots of contact cleaner and pulling the harness connector apart and reconnecting is as useful as a test light for chasing this sort of thing.

    the fuse for the keepalive circuit could also be dead.

    but failing those causes, since it's really rare for a plain old wire to fail open if it isn't messed with and it worked once, the cause is internal to the radio. they're all surface mount parts now, and almost all of it is several large multipurpose ICs... none availiable as service parts, and it takes a several-hundred dollar soldering station to even start messing with these things.

    the clock ought to be a separate chip, or part of the display controller, not part of the tuning synthesizer chip.

    the choice it seems to me is still between finding a tough dog, and not finding one, thus indicating a dead dog with a big price tag at the end of the harness.
  • hrb1hrb1 Member Posts: 1
  • swschradswschrad Member Posts: 2,171
    FM is OK because the fan motor brushes and the engine ignition (and possibly the fuel pump motor brushes) don't produce sharp enough spikes to put interference in the 88-108 MHz FM band. also, FM interference is reduced 10 to 1 or better simply by not using voltage-change (AM) modulation by any of the modern chip detectors.

    chopped to $10 words, you got ground and shield problems all over hell and gone, and it's going to take a while to fix 'em. not unusual nowadays, alas.

    first, find out where your engine control computer is... you will probably find there is a metal cover for it, and that cover is friction-grounded by one self-tap screw or a strap held by one or two self-tap screws. bend the strap in, and replace the self-tappers with stainless-steel bolts and nuts with lots of stainless-steel internal-tooth lockwashers, one every side of every transition from one item to another. if there is a screw someplace on the computer shield that you can use to bolt on a braided strap to this hard ground, all the better. if the material it is bolted onto is of dubious type, that is, not a big hunk of metal that bolts or is welded to another big hunk of metal that bolts or welds directly to the frame, run another big ground strap with bolts and lockwashers to the frame or a common engine grounding point.

    do lots of that wherever you have a DC motor in a metal case.

    if you have a library that has a copy of the ARRL Handbook, there is a section in most editions on chasing noise, those tips are good. in general, wherever anything can spark or has intermittent contacts, use of capacitors from hot to ground (I have had to bypass the ground wires as well on numerous occasions) from .005 to .25 mF at 50 volts or higher is called for to drain the radio noise. use short leads as close to the device as possible. if you have electronic geegaws making noise, a series coil (RF choke) that can handle twice the current rated in the 2.5 mH range or higher is great in series with the hot lead right at the case... but power consumption levels and the factory multiwire connectors mean you can't do this in automobiles. electronic geegaws can benefit from being bypassed by BOTH a high-capacity, like 1000 to 10,000 uF, and a low capacity, like .005 to .01 uF, capacitor.

    for the little noisemakers that remain, use of a CB radio (they are really sensitive in finding motor noise, and more common than a GP all-band shortwave or a 40 or 80-meter ham receiver) and a little ingenuity with fuses will help trace those issues. if you can turn the key to "run" and get noise for a few seconds, betcha it's the fuel pump... pull that fuse and try again to confirm it. I had a 90 ranger four-popper that was louder than anything, almost all the noise from the fuel pump, with a little from the wiper motor. I had to use a coaxial capacitor in the hot lead and a couple of other bypass capacitors hot-to-neutral and hot-to-frame underneath the drivers' position (the other bypass capacitors were a 1000 uF/35 volt and a 0.1 uF/250 volt) to damp that down to tolerable levels. should have bypassed right where the connector plugs into the fuel/level connector at the top of the tank... but it's a plastic tank, a rusty strap, my only car, and this is not a recipe for success and continued happy employment 20 miles from home.

    I have had to bypass a blower motor not only at the motor, but using 0.1 poly capacitors on every terminal of the speed-change resistor on a 76 Buick, along with an 8-gauge ground strap to the block, to show how much noise some sources make.

    old hams have had lots of experience in trying to clean up cars, so if somebody near you has more antennas than house, ask for tips if you get stuck. otherwise, use a transistor radio jammed between stations on the AM band as a detector to pass over suspect wiring and find hot spots that are the best places to put in-line filters to ground or run the lead through a coaxial capacitor. most wires going to a noise source DO have hot spots due to the wire becoming an antenna, and behaving in line with propagation theory.

    it's a pain, and you have to do a lot of good careful work and reinsulate lots of stuff (silicone rubber used liberally is really nice) to prevent electrical fires or corrosion. hacking things up may be interpreted to void warranties.

    if you listened to what passes for music these days instead of talk on AM, you might even be happier and more tolerant of the flaming idiots road-raging their way from lane 1 to lane 4 all day long... but if you have to stick with AM, you're going to have to get dirty and chase issues.

    good luck, it can be frustrating on the path and really rewarding at the end.
  • vovayavovaya Member Posts: 2
    Recently I had a crunching noice from speakers (especially on higher volumes). They are almost in sync with music (the louder music the louder noice). Put in new radio - even worse. It looks like radio doesn't have enough power to pump a volume, but why noise?
    This is 98 Maxima with regular radio. New unit is Pioneer DEH1400 CD receiver.
    Please advice.
  • fleetwoodsimcafleetwoodsimca Member Posts: 1,518
    Maybe the speakers are bad.
  • vovayavovaya Member Posts: 2
    Speakers were good. I just found that signal wire to the right rear speaker worned out and touched something (metal body probably).
    But now things look (and sound) really good!
  • fleetwoodsimcafleetwoodsimca Member Posts: 1,518
    Outstanding! A little leak-off or intermittent/partial ground would indeed mess up that speaker.
  • ateixeiraateixeira Member Posts: 72,587 discussed a single-point ground mod a while back. I wonder if that would have any effect on the radio (interference).

  • mtyfmtyf Member Posts: 19
    Hi there,
    I'm a little confused. My radio/CD player was working fine yesterday when I turned off my car before work. However, when I started her up again after work, all of a sudden it wasn't working. I put a CD in and it seems like it's reading it (the CD in light goes on and it makes CD player noises) but nothing comes out of the speakers. I have a 93 Altima GLE. Any ideas?
  • ateixeiraateixeira Member Posts: 72,587
    Harness came loose? Fuse blown? Just guessing.

  • okmomokmom Member Posts: 37
    the display on the radio/cd/cassette/clock on our 2000 Quest disappeared.
    Other than that everything else works perfectly.
    We are wondering it might be cheaper to get the radio/cd/cassette unit w/ free installation at the local electronic shop.(~$150)
    Can Any units that sell at the electronic shops works on my Quest? Ours has the control on the wheel.

  • swschradswschrad Member Posts: 2,171
    if they list units that are a drop-in replacement, and that meet your needs, it's almost certainly a savings.

    the high-colonic computerized gollywog psychedelic displays of the modern car radio sure are fragile, aren't they? and expensive, too, you don't fix 'em by just putting another 1829 bulb in the socket and pushing the radio back in the dash.

    mine scared me once, I scared it right back by buying a set of Ford radio pullers, and no further signs of trouble to this point. I keep my pullers close at hand for further psychological warfare with the radio, just in case.....
  • microrepairmicrorepair Member Posts: 508
    When I use the CD changer (trunk mounted) and the ambient temperature is above 75-80 degrees, I can hear a steady 15-20 hz clicking type noise that is NOT related to the engine speed but gets louder as I turn up the volume control. The cable is a copper cable (not fiber optic) to the head unit. This is not a changer problem. The first changer, which was new, did the same thing when the temperatures were above 80 degrees. That changer broke down after 2 1/2 years and I installed a used one until I could find a new one at a good price. The used one did the same thing. I then found a new one at a great price and the new one (#3) does the same thing except at a slightly lower temp range.
    After much thinking about this problem and analyzing the situation, it appears that it is more likely to hapen when I am in heavy traffic. This indicates that the engine compartment is heating up and possibly causing an electonics module to generate this noise which is being picked up by the copper cable to the trunk mounted CD. A few minutes after the vehicle has been moving at a reasonable speed (40-50 mph), the noise reduces in volume or disappears completely if the outside temp is at the low end of the range.
    If I turn off the engine while there is noise coming through the CD and run the CD on "accessory", there is NO noise.. So it is related to engine electronics being active..
    Any thoughts on this or do any other possibilities come to mind ?
  • swschradswschrad Member Posts: 2,171
    if so, get a snap-over ferrite from Radio Shack and snap it over the power leads to that fan. in fact, get two, and put one as close as you can to the temperature sensor, as well. might be RF interference caused by a sparking connection
  • fleetwoodsimcafleetwoodsimca Member Posts: 1,518
    You are amazing! Where did you learn that thar stuff? (:o]
  • swschradswschrad Member Posts: 2,171
    and I sure had a workout trying to get the whine out of the fuel pump leads on my '90 ranger while trying to get a CB to work in it. ended up having to peel the wires back under the drivers seat, drill a hole in the frame, and put three or four suppression capacitors (1500 uF, .01, l001, 5 pF) in parallel on each wire to ground to get enough of the crud down so I had an estimated 2 mV radiated signal, based on where it landed on the S-meter. man, you heard every passing Aerostar loud and clear from the same issue.

    took a LOT of silicone and broken twigs to waterproof that mess, but it never caused issues all the time I owned that truck.

    DC motors are / can be really lousy on generating radio-frequency interference. and it really hammers AM reception from the broadcast band up to the 50-60 MHz range sometimes. ARRL radio handbooks in the tube days used to have a dozen pages on RF noise suppression in mobile ham stations.
  • lcklcklcklck Member Posts: 3
    Hi, I'm going to replace the standard radio/tape, in my '96 Legacy wagon with an aftermarket radio/CD. Now the question: Who makes the best radio for this application. I don't want a "rolling boombox" just a "normal" radio/CD which will use the existing speakers, and do the job. I want an easily visible display, and I need a build-in clock, since that was what the original radio had. Which brand to buy?

    Thanks, larry.k
  • swschradswschrad Member Posts: 2,171
    put in your car data (year, model, etc.), find out what is availiable, open each one in another tab (or window, if you haven't installed mozilla yet), and see what looks good to you. then get something stirred up in the aftermarket forum and see what they like.
  • fleetwoodsimcafleetwoodsimca Member Posts: 1,518
    I bought a Sparkomatic by mail order one time, for my 1986 Olds Custom Cruiser. I used it to replace the burned out stock stereo unit. The guy I car pooled with at the time razzed me so immensely! Wow! The very name sounds like a joke, but we discovered I had really gotten a bargain on that close out deal. It was an EXCELLENT product.
  • lcklcklcklck Member Posts: 3
    I've visited the Crutchfield site, and the search capability is great. I found some 120 radio/CD units which will fit the car. I'm sure I can find one from that set which will suit me.

    Great site Crutchfield, very easy to use.

  • cnecoxcnecox Member Posts: 4
    My 2002 Legacy's radio antenna snapped off about an inch out from the base. I don't know why--it just did. I'm not sure if this will be covered by warranty. It looks like the antenna and the lead-in cable to the radio are all one piece. Does anyone know if their are replacements that will just screw into the base without replacing the cable? Seems like that might be pretty involved-going behind the radio up in the dash, etc.
  • ateixeiraateixeira Member Posts: 72,587
    See if your dealer will cover it. Did you see when it broke? Was it left up in a car wash or something like that?

    Insurance would cover it, but it's below any deductible you might have, and not worth making a claim.

    My Miata's power antennae broke, and I replaced it with a rubber whip model I got at Wal Mart for $12 or so. If you have access to the under side of the antennae, it's a piece of cake to swap out the whole thing.

  • irishalchemistirishalchemist Member Posts: 152
    Hi All,

    I have a Mazda Protege 1996 DX. I bought it used, and it came with an upgraded radio system. Basically, a CD controller, but no CD player. So, it's just a radio/cassette that has a bunch of inoperative buttons related to CD functions.

    In any case, the radio is Mazda OEM (has Mazda logo on it), is, according to the manual, a direct replacement for the Protege, and works fine.

    The only problem I have is the radio illumination. When I got the car, all the dashboard illumination stuff was pooched, but the radio was lit. I tracked it to a faulty dimmer switch, and repaired that (actually, just 'jumpered' to get max. illumination). Now, the dashboard lights work, but the radio lights are always 'ON' (they were always on, even when dashboard lights were pooched...). This is not too bad, but it's kind of annoying because the clock is hard to see (when the lights are 'ON', the clock lights are dimmer). Now, I followed every wiring diagram I could get my hands on, including Mazda's, and according to all this, if I plug +12v to the 'ILL' (illumination) lead on the radio (which comes from the dimmer switch), I should get a 'dark' radio. Well, no luck. Just to convince myself, I took apart the wife's car (another mazda), and when I put +12v to the 'ILL' lead on the radio, I do get the expected darkness.

    So the question is: Are there any Mazda OEM radios in which there is no such function (i.e., no dimming of the radio lights), or is there something iffy with that radio? By the way, I do suspect this, otherwise why would the dimmer switch be pooched in the first place... Also, could not find ANY information on the Mazda radio model (Model 340U...).

    Thanks for any advice.
  • swschradswschrad Member Posts: 2,171
    as to why you didn't just replace the dimmer rheostat. taking a dashboard off to replace the panel lights is a real stinker. they don't replace in radios, and haven't since the late 70s, that's an exchange job. they will need replacement faster if they are run on straight 12 volts.
  • irishalchemistirishalchemist Member Posts: 152
    Actually, my 'jumper' is a bit more involved than a simple 'wire'. I added a couple of diodes in series to have a ~ 2v voltage drop (thus the dashboard lights get 10v, and not 12v). Second, the TNS voltage (what goes to the panel lights once you turn on the lights) is rarely more than 11.5 volts (measured with a Fluke tester with data logger, and drove around while the tester was gathering data). Finally, these little bulbs (which you can get at RadioShack) are rated to work at 12v straight for more than 4000 hours.

    Now, back to the radio, my problem is that its lights do not dimm, no matter what I do (feed it 12v to the '-ILL' lead and nothing). I know my electronics 101 (I worked in a shop doing scientific instrument repairs), all I need is some information on my Mazda radio!

  • irishalchemistirishalchemist Member Posts: 152
    Forgot to mention why I did not buy the dimmer. It's a dealer item (have no time to go dig around in junk yards), and they basically want 75 bucks for a little piece of PCB board with transistors and resistors. Come to think of it, all it does is 'float the ground', so it should not be that hard to duplicate...
  • swschradswschrad Member Posts: 2,171
    light ratings and the real world are two different things. the reason we have halogen lights is that GE and Sylvania engineers noted that filaments run on DC tended to develop notches and failed prematurely when cycled on and off. halogen-cycle bulbs, even more than on AC, tend to fill in the notches with the cycle-returned filament metal, which reduced the shock-fail effect noticeably. 4000 hours is rated for continuous operation. I have had 50,000-hour rated indicators fail under DC, and the way that test stuff was built and used, they should have been 400-year bulbs.

    the traditional radio "lighting" lead has been direct to filaments, which went direct to ground. with all the vacuum fluorescent and LCD displays nowadays, instead of steady old lamp bulbs in the background, it may be used as a V/F (voltage to frequency) converter input or something equally subject to single-point failure.

    you could maybe determine if it's direct load or "magics" by putting a 0.1 ohm emitter resistor in series with that lead, putting the old Fluke across that resistor to measure its voltage drop, and use a little old I = E/R to see how much current is being drawn. under a milliamp, they are using "magics" and you really do need some service data... or the factory dim module. two to five milliamps, it's probably a vacuum-fluorescent filament circuit or a segment-scan voltage source, and I'd try coming the other way, from zero volts, and see what the result is. ten or more milliamps, you just haven't dropped the voltage enough yet, try getting down in the 7 to 10 range where much of the difference in light level should be. dim a bare bulb with resistors and you'll see that there isn't a lot of visible change between 13.8 volts charging and 10 volts, but you should notice the drop to 7 or 8 volts as a big change in "brightness."

    good luck finding the REAL information, but this might help some. how about using an LM-318 or LM-323 variable voltage switching regulator so you can dial down continuously to about a volt and a half under load, with just one pot, one chip, and two noise-suppression caps? all radios that fit into that dash hole should be compatible with the factory lighting lead's voltage source, so I can't help thinking that at the end of the day, anything between zero and +BATT will be tolerated by the radio. LM-318 is good for an amp without heat sink, amp and a half with one, and the LM-323 will supply five amps with heat sink. a bare LM-318 is almost certain to fix your woes, I would think, and sounds like you've been diddling with electrons on the side enough to whip one into circuit and into the dash quickly.
  • irishalchemistirishalchemist Member Posts: 152
    Really, thanks a lot! Good info in your post. I was thinking about the voltage regs, particularly the LM318, and a pass transistor. I think, counting all the 194 bulbs behind the instrument panel (2), and all the microbulbs (at 60 mA a piece), the regulator should be able to handle 2 amps or so. That means, the bare 318 will be toast in no time (only 1.5 amps). Also, the problem of going this way is that you get a 1.5 volt drop with any of these regulators, so you usually need 15v to get a nice 12v...

    In any case, I think that I can control the duty cycle of a 3055 (which handles 90 watts...) with a 555 timmer. If I etch (spelling?) a board that fits the board on the dimmer switch, I could easily fit everything on the current switch housing, and even use it's nice little pot to control the triggering of the 555 (varying the RC constant...).

    In any case, what you said about the illumination lead of the radio being able to handle anything from 0 to +BATT gives me more confidence on what I'm doing. Personally, I think that the guy who owned the car before had it installed and they botched the installation (thus the burnt dimmer in the first place).

    Well, it will be cheaper (10 bucks for all parts), but it'll take a while. In any case, all this talk brings back good memories. I will have to find where the heck I stored that protoboard I had...

  • swschradswschrad Member Posts: 2,171
    yeah, by all means... what's the dash fuse, something like 10 or 15 amps? might want to use a pair of 3055s with some half-ohm balance resistors series on the emitters. I whipped up a little pass-transistor train speed control in HS, and with an amp draw, that tranny (I think it was a TR-02, universal 2n554 replacement) lasted three minutes. so you will want to find a place to stash a remote heat sink if you have appreciable drain, and I would expect at least 5 amps now that you caught me in a contradiction.

    as for the botched install... truth be told, there are a lot of "professional installers" that secretly hope to be hired as the new "rally monkey" if the present one falls off the scoreboard. I had a dealer guy futz around ordering the wrong radio for my car by using acid flux and eighth-inch solder to tack-solder harness wires directly to a different one in the mid-70s, and had an installer sorta hack up the radio cutout expanding it one millimeter to replace a wimpy factory radio with an "exact fit" sony in 96.

    have fun breadboarding! -- I'm almost done restoring an old Philco 65 chassis in a 155 (?) table case for something different.
  • irishalchemistirishalchemist Member Posts: 152
    I got all the stuff and made a little protoboard. It works fine with a 0.25 amp load (a single 194 bulb...). Now I have to bring all this mess down to the car and try it out (this weekend's project).

    As for multiple transistor pass gates (that's how I called them), oh boy, I rather stay away from them. One of the instruments I maintained was an old NMR (the research version or the MRI used in medicine). It had a controlled 100v, 100 amp power supply (with a ripple of less than 1 ppm), and it had a pass gate with 16 big'ol transistors (those that bolted to the heatsink, which was watercooled in my case). I remember one blew, and we had to replace ALL of them because we could not get them balanced - One always drew more current and invariably burnt. In any case, a single 3055 (or equivalent) should handle 3 to 5 amps at 12 volts. That 'should' be plenty...

    As for the botched install, I actually took the radio out and there was nothing wrong with the harnesses (that I could tell). So my guess is that this Mazda radio is like some aftermarket radios I've seen which don't dimm the lights with the dimmer switch. Some even have their own dimming mechanism. The only way to find out would be to move my car's radio to the wife's car, but she's not thrilled about that.

    Thanks for all the help and ideas. I will give an update when I test it on the car...

  • swschradswschrad Member Posts: 2,171
    you ever see the power supply for one of the old Varian medical accelerators, the ones that occasionally "went wild" according to 60 minutes? looked like the high-power section of a 5 KW radio transmitter, including two 3cx2500 tubes (think 5-gallon water jugs with plate caps and glass chimneys.)

    I agree, balancing transistors is the pits, you should shotgun all the emitter resistors as well when you get after a heat sink full. it does matter more if you are putting out big-[non-permissible content removed] pulses than if you are not running several hundred audio watts most of the time.
  • irishalchemistirishalchemist Member Posts: 152
    Wow - The NMR I was talking about was also Varian! The power supply, which powered a big magnet, consisted of a transformer that weighed in at ~ 200 pounds, and a big rectification circuit. This was three SCRs (the big ones, bolted to the same watercooled heatsink), each of which was itself triggered by another, smaller, SCR. The three phases rectified were combined, then passed through a bank of capacitors (each one was a 'quart' in size, and had screws to hold them to the boards), and this went to the transistor pass gate, which was controlled by the feedback from the magnet (to keep the magnetic field steady).

    I remember one time one of the phases was not triggering properly and I started mucking around with a scope. I accidentally shorted one of the large, 50 AMP, SCRs, and the thing blew up with a huge bang and sparks. I had little bits of SCR casing impaled in my arms (it was like glass shreds - no fun...). It was then than I started understanding what people meant when they said that someone 'was so scared that he had sh*t his pants' (you make your own conclusions...).

    Anyway, too much nostalgia. The circuit works fine with the load from the dashboard lights. The 3055 does not even get warm, so I think the actually load is much less than what I imagimed (anyway, I learned to design with a worst-case scenario approach). I tried today with the car. I don't think I can drive around with the cables coming off the dashboard and the protoboard floating there, so this week I will have to remember the old skill of etching PCB board. More later.

  • swschradswschrad Member Posts: 2,171
    varian did a lot of medical equipment in the 1980s, the whole scanning tomography field was wide open and everybody dove in. the x-ray giants were well positioned, of course, and varian built some of the best high voltage, high-frequency, high current transmitting tubes and components, so it was to be expected they would buy a few smaller outfits and go there. I should also say I screwed up in describing that power supply, 3cx series tubes are ceramic... this used the 3-2500Z series, big honking glass bottles about halfway between the size of washer fluid gallon jugs and 5-gallon water jugs. two of those with sockets and chimneys cost what a chevy nova did.

    back to dashboard controls... yeah, there is a lot less power loss (and heat) to take care of when you use a switched power supply to cut the voltage down into a load, so that transistor will do fine.

    if you can fix those money-suckers, you can probably even figure out how to light up a bad front panel on the current crop of car radios :-D -- that's a real load of one-off displays from Hell ;)
  • matty3matty3 Member Posts: 5
    I have blown the stock subwoofer under the drivers seat of my 1997 Subaru GT wagon. Does anyone know where to get a new speaker, or know what size the stock woofer is? I contacted Crutchfield, but they were unable to help. Thanks.
  • fleetwoodsimcafleetwoodsimca Member Posts: 1,518
    Could you just leave it like it is? (:o]
  • swschradswschrad Member Posts: 2,171
    you can always go to dealer parts. as an alternative, get to the speaker, measure its depth from the back of the front panel, its width across the mounting plate, and start looking for replacements with that data.
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